Interaction of animal cells (of one animal species) with viruses produces a protein which can confer resistance to infection from a wide range of viruses on fresh animal cells of the same species. The protein is interferon.
Considerable is known about interferon, its preparation and activity, as reflected in "The Merck Index", eighth edition, page 568, Merck & Co., Inc., 1968, and "McGraw-Hill Encyclopedia of Science and Technology", third edition, volume 7, pages 221 and 222, 1971, and further references cited in these texts. Production of mouse interferon is described by Finter, N. B., Nature, Vol. 206, pages 597 to 599, May, 1965.
There are huge investments in fur-bearing animals, e.g. mink, and in domestic animals, such as cows, horses, swine and poultry, particularly meat-providing animals, which are subject to viral attack. Preventing or checking such viral attack would go a long way toward protecting such investments.
When a body receives a viral infection, the body, under normal, natural circumstances, produces interferon. This interferon spreads from one cell to adjacent cells or is circulated through the circulatory system throughout the body so the whole body is affected. Interferon operates to interfere with reproduction and spread of virus; thus, in effect, it checks or prevents viral infection.
Interferon is essentially species specific, but not virus specific. Interferon produced in one species of animal or in organs of one species of animal is essentially effective only in that species. However, interferon produced by the use of one virus has been found to be effective for preventing or checking the spread of many other viruses.